Hybrid cement clinker and cement made from that clinker

ABSTRACT

A hybrid cement clinker incorporates specific ranges of clinker phases and falls within specific modulus values as set forth and described in this document.

This utility patent application claims the benefit of priority in U.S. Provisional Patent Application Ser. No. 61/814,854 filed on Apr. 23, 2013, the entirety of the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

This document relates generally to the field of cement clinkers and cement.

BACKGROUND

Cement is a very important construction material and world production has exceeded over 3 billion tons per year in recent years. In order to save resources and protect the environment, it is important to reduce the consumption of raw materials and reduce the energy used in cement production.

This document relates to a new and improved hybrid cement clinker and cement that utilizes waste and byproducts of other industrial processes while providing enhanced performance and environmental characteristics. The hybrid cement clinker and cement incorporate the best aspects of ordinary Portland cement and calcium sulfoaluminate cement. The new and improved hybrid cement is a ferrite-alite-calcium sulfoaluminate (CSA) cement that is less expensive to produce than conventional CSA cements and is much more energy efficient than ordinary Portland cement (OPC) with greatly reduced carbon emissions and similar performance.

SUMMARY

In accordance with the purposes and benefits described herein, a hybrid cement clinker is provided. The hybrid cement clinker includes the following clinker phases: about 20-55 weight percent C₃S, about 5-25 weight percent C₂S, about 10-20 weight percent C₄A₃ S, about 5-50 weight percent C₄AF, about 3-7 weight percent CŚ, and about 0.5-1.0 weight percent CaF₂. The clinker further has a lime adequate degree (LAD) modulus value of between about 0.8 and about 0.96, a ratio of silicates and aluminates (RSA) modulus value of between about 0.3 and about 4.0, a ratio of sulfoaluminates and ferroaluminates (RSF) modulus value of between about 0.2 and about 4.0, a sulfur excessive coefficient (SEC) modulus value of between about 0.4 and about 2.3 and a quantity of liquid phase (QLP) modulus value of between about 0.08 and about 0.12.

More specifically describing the cement clinker, the clinker has a LAD modulus value of between 0.86 and about 0.94, a RSA modulus value of between 0.5 and about 2.5, a RSF modulus value of between 0.3 and about 1.5, a SEC modulus value of between about 1.0 and about 1.7 and a QLP modulus value of between about 0.09 and about 0.11.

The cement clinker may incorporate a waste material selected from a group consisting of stainless steel pickling sludge, Bayer red mud, fluidized bed combustion spent bed material, air cooler blast furnace slag, iron casting slag, carbide lime, aluminum dross and mixtures thereof. Further the clinker may include between 0.05 and 1.0 weight percent of triisopropanolamine (TIPA).

In one particularly useful embodiment the clinker is substantially free of C₃A. In one particularly useful embodiment the cement clinker further includes between 675-725 kg of limestone per ton of clinker. In one particularly useful embodiment the cement clinker comprises about 35-41 weight percent C₃S, about 10-15 weight percent C₂S, about 14-16 weight percent C₄A₃ S, about 20-26 weight percent C₄AF and about 4-6 weight percent CŚ, and about 0.7-0.85 weight percent CaF₂ fired at a temperature of about 1250-1300° C. In one particularly useful embodiment that clinker has a LAD modulus value of between about 0.88 and about 0.92, a RSA modulus value of between about 1.0 and about 1.7, a RSF modulus value of between about 0.5 and about 0.8, a SEC modulus value of between about 1.0 and about 1.6 and a QLP modulus value of between about 0.095 and about 0.105.

These and other embodiments will be set forth in the description which follows, and in part will become apparent to those of ordinary skill in the art by reference to the following description.

DETAILED DESCRIPTION

Disclosed herein is a ferrite-alite-calcium sulfoaluminate cement or F/A-CSA that is very high in ferrite (C₄AF) at concentrations of up to 50% by weight, that also contains high contents of both Klein's compound (C₄A₃ S) and Alite (C₃S). This cement will be less expensive to produce than conventional CSA cements, and be much more energy efficient than ordinary Portland cement (OPC) with greatly reduced carbon emissions and similar performance.

The presence of both Klein's compound (the calcium sulfoaluminate in CSA) and alite is unusual, as these two materials are generally considered thermally incompatible, alite not typically forming below 1300° C. and Klein's compound beginning to decompose at 1300° C.-1350° C.

This cement was fabricated with the help of CaF₂ which is both a known flux and mineralizing agent for alite. In this system it forms the compound fluorellestadite (Ca₁₀(SiO₄)₃(SO₄)₃F₂) which has a melting temperature of 1245° C. forming a flux. It has been found that in the presence of fluorellestadite the melting temperature of ferrite decreases from about 1368° C. to 1269° C. and the melting point of fluorellestadite decreases to as low as 1204° C. The presence of a low temperature liquid phase accelerates the reaction of C₂S (belite) with C (lime) to form C₃S. In a totally dry system this solid-solid reaction is extremely slow.

The use of the flux has allowed the definition of a reasonable thermal regime where Klein's compound, and alite along with belite and high levels of ferrite can co-exist (1250° C. to 1275° C. and 30 to 60 minutes of retention time). The compositions of cement produced in this regime have very low levels of free lime, indicating that it is fully reacted and very low levels of C₃A, a thermal decomposition product of Klein's compound, indicating that it is not over-fired.

Triisopropanolamine (TIPA) further helps the ferrite to fully hydrate relatively quickly. Typically ferrite is not considered to contribute significantly to the strength of OPC products due to its very slow rate of hydration. TIPA is most likely acting as a chelating agent with the iron keeping it from forming iron oxy-hydroxides which can form coatings and stop the hydration process.

Also with TIPA and sufficient levels of gypsum (>10% by weight), we find that there is no interference with the silicate hydration and C—S—H gel formation, which is also very important, as in conventional CSA systems the silicates do not contribute much to strength, at least early strength. The silicates in typical CSA are mostly in the form of C₂S (belite) which also hydrates slowly. In our activated F/A-CSA formulation, ferrite is a former of ettringite, the principal cement forming product of CSA.

The F/A-CSA cement reduces the amount of bauxite needed for fabrication of CSA by more than ⅔, greatly reducing its cost. Further, the iron-rich formulation also enables the use of large quantities of red mud, an abundant and potentially dangerous industrial waste, reducing cost and greatly enhancing its benefit. Other industrial waste products such as stainless steel pickling sludge, which is high in iron and CaF₂, and fluidized bed combustion waste, high in calcium and sulfate, can be utilized as demonstrated. In addition, the use of industrial by-products, calcium sulfate, and the bauxite greatly lowers the limestone content of the F/A-CSA cement formulation resulting in lower CO₂-emission from mineral calcination. Advantageously, the use of fluxes and mineralizers, CaF₂ and CaSO₄, allows F/A-CSA to be produced at very low firing temperature—1250° C.-1275° C., 150° C. to 200° C. lower than OPC, making this cement energy efficient and further lowering the carbon emissions. Further, the cement is also activated with gypsum or anhydrite which is added at a rate of 10% to 30% (depending on ferrite content) to the F/A-CSA cement, further reducing carbon emissions. Typically, the clinker formulation includes between about 0.5 and about 1.0 weight percent CaF₂. More preferably, the clinker formulation typically includes between about 0.7 and about 0.85 weight percent CaF₂.

The F/A-CSA cement has a high concentration of alite which is the most reactive component in OPC. If the cement is properly sulfated, the alite component fully hydrates to C—S—H gels greatly contributing to the strength and stability of the cement and its mortar or concrete products. The belite contained in many CSA cements is found to hydrate very slowly if at all contributing little to the strength.

The F/A-CSA cement also has a high content of Klein's compound which is the principle cementitious agent for CSA cements producing the high early strength characteristics of CSA. Advantageously, the use of alcohol amines (more specifically TIPA), at a rate of 0.05-1.0% by weight of cement (i.e. clinker+gypsum), results in the full hydration of the ferrite in the F/A-CSA cement and subsequent ettringite formation, also greatly contributing to its stability. Still further, the combination of alite, Klein's compound and active ferrite results in a high performance cement that is comparable to OPC and conventional CSA cements.

DEFINITIONS

-   -   A. Clinker Phases         -   1. C₃S—alite, tricalcium silicate, 3CaO.SiO₂         -   2. C₂S—belite, main constituent is dicalcium silicate,             2CaO.SiO₂         -   3. C₄A₃ S—Klein's compound, calciumsulfoaluminate,             Ca₄(AlO₂)₆SO₄         -   4. C₄AF—ferrite or tetracalcium aluminoferrite,             4CaO.Al₂O₃.Fe₂O₃         -   5. C₃A—tricalciumaluminate, 3CaO.Al₂O₃     -   B. Modulus Values         -   1. Designing of Representative Controlled Modulus Values for             FA-CSA Cement Clinkers—As more modulus values are needed for             designing the FA-CSA cement, it is more difficult to             calculate the proportions of raw materials of FA-CSA cements             than that of Portland cements. The modulus values are             similar to that of the Portland cement with but have to be             modified. For example, because the phases C₃S and C₂S exist             in the FA-CSA cement clinker simultaneously, the Lime             Saturation Factor is adopted to evaluate the possible degree             of conversion from C₂S to C₃S. Due to the different chemical             and mineral compositions, the formula of Lime Saturation             Factor for FA-CSA cement will be different from that of             Portland cement. To distinguish them, the symbol of Lime             Saturation Factor for FA-CSA cement can referred to as LAD             (Lime Adequate Degree). LAD can be definite as the ratio             between the rest CaO after being absorbed by C₄AF and C₄A₃ S             and the CaO needed by C₃S if all SiO₂ is converted to C₃S.             -   The second modulus value adopted for FA-CSA cement                 clinker is RSA (Ratio of Silicates and Aluminates),                 which is similar to the SM for Portland cement. But RSA                 is definite as ratio of silicates and aluminates of                 FA-CSA cement directly.             -   The third modulus value RSF (Ratio of Sulfoaluminate and                 Ferroaluminate) is adopted to describe the ratio between                 C₄A₃ S and C₄AF.             -   The fourth modulus value is SEC (Sulfur Excessive                 Coefficient). The modulus SEC is defined as the specific                 value between the remaining quantity of SO₃ in the                 clinker deducting the quantity of SO₃ corresponding to                 the quantity of CaSO₄ needed for the formation of liquid                 phase in the clinker and the quantity of SO₃ requested                 for forming the mineral phase C₄A₃ S completely.                 Usually, in order to form sufficiently, the practical                 quantity of SO₃ is larger than needed in FA-CSA clinker,                 i.e. SEC is greater than 1.00, which is why we named it                 as SEC.             -   The fifth and last modulus value is QLP (Quantity of                 Liquid Phase). The definition of QLP is the percentage                 of liquid phase in the clinkers.         -   2. Assumptions in the Calculation of Modulus Values             -   a) The principal mineral phases in the FA-CSA cement                 clinkers are C₃S, C₂S, C₄A₃ S, C₄AF and CaSO₄ while                 minor mineral phases are neglected;             -   b) All Fe₂O₃ of the raw meal will form the mineral phase                 C₄AF completely with the consumption of corresponding                 Al₂O₃ and CaO;             -   c) The remaining Al₂O₃ in the raw meal will form C₄A₃ S                 completely, and the corresponding CaO and SO₃ will be                 consumed;             -   d) All the silicon dioxide (SiO₂) of the raw meal forms                 C₂S. The remaining lime (CaO) reacts with C₂S to form                 C₃S.             -   e) The main liquid phase for the formation of mineral                 phases in FA-CSA cement clinker is fluorellestadite                 (3C2S.3CaSO₄.CaF₂). The Quantity of Liquid Phase (QLP)                 depends on the percentage of CaF₂ and CaSO₄ added into                 the raw meal.         -   3. Equations for Calculating the Modulus Value—As mentioned             above, the main mineral phases in FA-CSA cement are C₃S,             C₂S, C₄A₃ S and C₄AF. Usually a little bit surplus of CaO             and CaSO₄ is provided to ensure that C₄A₃ S and C₃S can be             formed sufficiently. Therefore phases CaSO₄ and f_(CaO) can             exist in the clinker. All phases in FA-CSA clinker and the             percentages of oxides for them are shown in table 1.

TABLE 1 Percentages of oxides in main mineral phases of FA-CSA clinker Percentages of Oxides in mineral phases/% Oxides C₃S C₂S C₄A₃ S C₄AF CaSO₄ f_(CaO) CaO 73.6838 65.1158 36.7565 46.1577 41.1905 100 SiO₂ 26.3162 34.8842 Al₂O₃ 50.1237 20.9813 Fe₂O₃ 32.8610 SO₃ 13.1197 58.8095

-   -   -   4. Calculation of LAD—Assuming Fe₂O₃ is absorbed to form             C₄AF completely, the corresponding consumption of Al₂O₃ is             0.6385Fe₂O₃, where 0.6385=20.9813/32.8610. The rest of Al₂O₃             that can be absorbed in C₄A₃ S will be Al₂O₃-0.6385Fe₂O₃. In             the same time, the corresponding SO₃ will be consumed as             0.2618(Al₂O₃-0.6385Fe₂O₃). The rest SO₃ existed in CaSO₄ is             SO₃-0.2618(Al₂O₃-0.6385Fe₂O₃), the corresponding CaO of             CaSO₄ is:

0.7004[SO3-0.2618(Al2O3-0.6385Fe2O3)]

-   -   -   -   Where:

0.7004=41.1905/58.8095

-   -   -   -   The consumption of CaO by C₄AF is:

1.4046Fe₂O₃

-   -   -   -   Where:

1.4046=46.1577/32.8610

-   -   -   -   The consumption of CaO by C₄A₃ S is:

0.7333(Al₂O₃-0.6385Fe₂O₃)

-   -   -   -   Where:

0.7333=36.7565/50.1237

-   -   -   -   Therefore the total CaO that can be absorbed by SiO₂ is:

(CaO-f _(CaO))-0.7004[SO₃-0.2618(Al₂O₃-0.6385Fe₂O₃)]-1.4046Fe₂O₃-0.7333(Al₂O₃-0.6385Fe₂O₃)═(CaO-f _(CaO))-0.5499Al₂O₃-1.0534Fe₂O₃-0.7004SO₃

-   -   -   -   According to the definition of LAD, the equation for LAD                 will be:

${LAD} = \frac{\begin{matrix} {\left( {{CaO} - f_{CaO}} \right) - {0.5499\mspace{11mu} {Al}_{2}O_{3}} -} \\ {{1.0534\mspace{11mu} {Fe}_{2}O_{3}} - {0.7004\mspace{11mu} {SO}_{3}}} \end{matrix}}{2.7999\mspace{11mu} {SiO}_{2}}$

-   -   -   -   Where:

2.7999=73.6838/26.3162

-   -   -   -   It is the mass ratio of calcium oxide and silicon                 dioxide when all SiO₂ convert into C3S.

        -   5. Deduction of RSA—According to table 1, the relationships             between chemical compositions and mineral compositions of             clinker can be obtained as the following linear equations:

$\begin{matrix} \left\{ \begin{matrix} {{CaO} = \begin{matrix} {{0.7368C_{3}S} + {0.6512C_{2}S} + {0.3676C_{4}A_{3}\overset{\_}{S}} +} \\ {{0.4616C_{4}{AF}} + {0.4119{CaSO}_{4}} + f_{CaO}} \end{matrix}} \\ {{SiO}_{2} = {{0.2632C_{3}S} + {0.3488C_{2}S}}} \\ {{{Al}_{2}O_{3}} = {{0.5012C_{4}A_{3}\overset{\_}{S}} + {0.2098C_{4}{AF}}}} \\ {{{Fe}_{2}O_{3}} = {0.3286C_{4}{AF}}} \\ {{SO}_{3} = {{0.1312C_{4}A_{3}\overset{\_}{S}} + {0.5881{CaSO}_{4}}}} \end{matrix} \right. & \left( {4\text{-}15} \right) \end{matrix}$

-   -   -   -   The mineral compositions of the FA-CSA clinker can be                 calculated as follow by solving the equations above.

$\quad\left\{ \begin{matrix} {{C_{3}S} = \begin{matrix} {{4.0715\left( {{CaO} - f_{CaO}} \right)} - {7.5999{SiO}_{2}} -} \\ {{2.2393{Al}_{2}O_{3}} - {4.2892{Fe}_{2}O_{3}} - {2.8517{SO}_{3}}} \end{matrix}} \\ {{C_{2}S} = \begin{matrix} {{8.5999{SiO}_{2}} + {1.6893{Al}_{2}O_{3}} +} \\ {{3.2357{Fe}_{2}O_{3}} + {2.1513{SO}_{3}} - {3.0715\left( {{CaO} - f_{CaO}} \right)}} \end{matrix}} \\ {{C_{4}A_{3}\overset{\_}{S}} = {{1.9951{Al}_{2}O_{3}} - {1.2738{Fe}_{2}O_{3}}}} \\ {{C_{4}{AF}} = {3.0431{Fe}_{2}O_{3}}} \\ {{CaSO}_{4} = {{1.7004{SO}_{3}} - {0.4451{Al}_{2}O_{3}} + {0.2842{Fe}_{2}O_{3}}}} \end{matrix} \right.$

-   -   -   -   As the definition described above, RSA can be expressed                 as follow:

${RSA} = \frac{{C_{3}S} + {C_{2}S}}{{C_{4}A_{3}\overset{\_}{S}} + {C_{4}{AF}}}$ ${i.e.{RSA}} = \frac{\begin{matrix} {\left( {{CaO} - f_{CaO}} \right) + {SiO}_{2} -} \\ {{0.5500{Al}_{2}O_{3}} - {1.0535{Fe}_{2}O_{3}} - {0.7004{SO}_{3}}} \end{matrix}}{{1.9951{Al}_{2}O_{3}} + {1.7693{Fe}_{2}O_{3}}}$

-   -   -   6. Deduction of RSF—As the definition of RSF described             above, RSF can be expressed as follows:

${RSF} = \frac{C_{4}A_{3}\overset{\_}{S}}{C_{4}A\; F}$

-   -   -   -   Thus:

${RSF} = {{0.6556\frac{{Al}_{2}O_{3}}{{Fe}_{2}O_{3}}} - 0.4186}$

-   -   -   7. Deduction of SEC—As the Al₂O₃ needed in C₄AF is             0.6385Fe₂O₃, the rest Al₂O₃ will be Al₂O₃-0.6385Fe₂O₃ which             can be absorbed by C₄A₃ S, thus formula of SEC is as             follows:

${SEC} = \frac{{SO}_{3} - {3.0766{CaF}_{2}}}{{0.2617{Al}_{2}O_{3}} - {0.1671{Fe}_{2}O_{3}}}$

-   -   -   -   Where: CaF₂ is the percentage of CaF₂ in the clinker. It                 can be decided by the QLP.

        -   8. Deduction of QLP—Because the SO₃ in the clinker is             designed enough and the liquid phase can be formed at the             lower temperature, the QLP will depend on the quantity of             CaF₂ in the clinker. Thus,

${QLF} = {{\frac{M_{L}}{M_{{CAF}_{2}}} \times {CaF}_{2}} = {12.8494{CaF}_{2}}}$

-   -   -   -   Where:                 -   M_(L) is molecular weight of liquid phase.

        -   9. The Relationship between Modulus Values and Mineral             Compositions There are two ways to calculate the mineral             compositions of FA-CSA clinker. The first one is to             calculate by using chemical compositions of clinker; and the             second one is to calculate according to the modulus value.             The mineral compositions calculated by chemical compositions             are shown in the equations above. The mineral compositions             calculated by modulus values can be deduced as follows:             -   The LAD value also can be described as follow when the                 mineral compositions are used:

${LAD} = \frac{{C_{3}S} + {0.8835\; C_{2}S}}{{C_{3}S} + {1.3253\; C_{2}S}}$

-   -   -   -   The modulus value SEC can also be written as:

${SEC} = \frac{{0.1312C_{4}A_{3}\overset{\_}{S}} + {0.5881\left( {{CaSO}_{4} - {5.2315{CaF}_{2}}} \right)}}{\begin{matrix} {{0.2617\left( {{0.5012C_{4}A_{3}\overset{\_}{S}} + {0.2098C_{4}{AF}}} \right)} -} \\ {0.1671 \times 0.3286C_{4}{AF}} \end{matrix}}$

-   -   -   -   It can be simplified as follow:

${SEC} = {1 + {4.4825 \times \frac{{CaSO}_{4} - {5.2315{CaF}_{2}}}{C_{4}A_{3}\overset{\_}{S}}}}$

-   -   -   -   The RSA and RSF are shown as follows respectively                 according to their definitions.

${RSA} = \frac{{C_{3}S} + {C_{2}S}}{{C_{4}A_{3}\overset{\_}{S}} + {C_{4}{AF}}}$ ${RSF} = \frac{C_{4}A_{3}\overset{\_}{S}}{C_{4}{AF}}$

-   -   -   -   Because C₄AF=3.0431Fe₂O₃, the percentages of other                 mineral phases can be calculated easily. The detailed                 results will be omitted.

        -   10. Definition of a Range of Useful Modulus Values—The free             lime content is a measure of the extent in which the raw             materials have reacted to form clinker phases. Free lime             contents above about 2% are generally not acceptable and a             target of less than 1% was used here. The free lime contents             measured on each clinker fired at 1300° C. for 30 minutes             are displayed in table 2 below. The free lime content is             correlated to the modulus values, and optimum/range values             can be drawn from all these experiments.             -   The following matrix of tests were run:             -   LAD=0.88, 0.90, 0.92, 0.94 when RSA=3.00, RSF=2.00,                 SEC=1.40 and QLP=0.10;             -   RSA=0.50, 1.00, 2.00, 3.00, 4.00, ∞(9967) when LAD=0.92,                 RSF=2.00, SEC=1.40, QLP=0.10;             -   RSF=0.50, 1.00, 2.00, 4.00 when LAD=0.92, RSA=3.00,                 SEC=1.40, QLP=0.10;             -   SEC=1.00, 1.20, 1.40, 1.60 when LAD=0.92, RSA=3.00,                 RSF=2.00, QLP=0.10;             -   QLP=0.06, 0.08, 0.10, 0.12 when LAD=0.92, RSA=3.00,                 RSF=2.00, SEC=1.40.

TABLE 2 Clinker, Modulus and Corresponding Free Lime Content Clinker Compositions Modulus Values F. Lime Samples C₃S C₂S C₄A₃ S C₄AF CŚ LAD RSA RSF SEC QLP 1300° C. SC-01 49.56 20.96 15.63 7.81 5.46 0.88 3.00 2.00 1.40 0.10 0.64 SC-02 53.33 17.18 15.63 7.81 5.46 0.90 3.00 2.00 1.40 0.10 0.70 SC-03 56.97 13.54 15.63 7.81 5.47 0.92 3.00 2.00 1.40 0.10 0.85 SC-04 60.51 10.01 15.63 7.81 5.47 0.94 3.00 2.00 1.40 0.10 0.92 SC-05 24.99 5.89 40.68 20.34 7.70 0.92 0.50 2.00 1.40 0.10 1.82 SC-06 37.59 8.91 30.80 15.40 6.82 0.92 1.00 2.00 1.40 0.10 1.23 SC-07 50.45 11.98 20.74 10.37 5.92 0.92 2.00 2.00 1.40 0.10 0.79 SC-03 56.97 13.54 15.63 7.81 5.47 0.92 3.00 2.00 1.40 0.10 0.85 SC-08 60.92 14.48 12.54 6.27 5.19 0.92 4.00 2.00 1.40 0.10 0.78 SC-09 76.92 18.31 0.01 0.00 4.07 0.92 ∞9967 1.91 1.18 0.10 0.96 SC-10 57.35 13.63 7.87 15.74 4.77 0.92 3.00 0.50 1.40 0.10 0.42 SC-11 57.16 13.59 11.76 11.76 5.12 0.92 3.00 1.00 1.40 0.10 0.61 SC-03 56.97 13.54 15.63 7.81 5.47 0.92 3.00 2.00 1.40 0.10 0.85 SC-12 56.83 13.50 18.70 4.67 5.74 0.92 3.00 4.00 1.40 0.10 0.98 SC-13 57.79 13.74 15.86 7.93 4.07 0.92 3.00 2.00 1.00 0.10 0.43 SC-14 57.38 13.64 15.74 7.87 4.77 0.92 3.00 2.00 1.20 0.10 0.79 SC-03 56.97 13.54 15.63 7.81 5.47 0.92 3.00 2.00 1.40 0.10 0.85 SC-15 56.58 13.44 15.51 7.76 6.15 0.92 3.00 2.00 1.60 0.10 0.97 SC-16 58.10 13.82 15.95 7.97 3.86 0.92 3.00 2.00 1.40 0.06 1.53 SC-17 57.54 13.67 15.79 7.89 4.66 0.92 3.00 2.00 1.40 0.08 1.16 SC-03 56.97 13.54 15.63 7.81 5.47 0.92 3.00 2.00 1.40 0.10 0.85 SC-18 56.42 13.39 15.47 7.73 6.26 0.92 3.00 2.00 1.40 0.12 0.61

-   -   -   -   Low free lime content are obtained with these modulus                 values:                 -   Low LAD value range from 0.88 to 0.94;                 -   RSA>2;                 -   Low RSF (<2);                 -   SEC low, close to 1.20;                 -   QLP close to 0.10.             -   Based on the data however the following broader range of                 modulus values produced good results.             -   Five compositions were formulated from Reagent Chemicals                 (RC) as displayed in table 3 below. The ferrite content                 varied from 5% to 45% by weight from compositions #1 to                 #5. Some parameters were constant through all these                 formulations, such as LAD at 0.88, SEC at 1.20 and QLP                 at 0.10.

TABLE 3 Additional examples of modulus values Composition Number #1 #2 #3 #4 #5 Modulus LAD 0.88 Values RSA 3.63 2.09 1.32 0.86 0.54 RSF 3.01 1.00 0.60 0.43 0.33 SEC 1.20 QLP 0.10 Chemical Ca(OH)₂ 63.73 60.85 58.02 55.18 52.32 Formulations SiO₂ 17.06 14.67 12.31 9.96 7.60 Al(OH)₃ 10.68 13.27 15.83 18.38 20.95 Fe₂O₃ 1.34 4.03 6.70 9.34 12.0 CaSO₄ 6.56 6.55 6.52 6.51 6.50 CaF₂ 0.64 0.64 0.63 0.63 0.63 Chemical CaO 61.42 58.94 56.50 54.02 51.52 Compositions SiO₂ 20.96 18.07 15.21 12.34 9.44 Al₂O₃ 8.56 10.67 12.76 14.86 16.98 Fe₂O₃ 1.64 4.94 8.23 11.50 14.81 SO₃ 4.76 4.76 4.78 4.76 4.77 CaF₂ 0.78-0.79 Clinker C₃S 50.90 43.95 36.96 30.00 22.88 Composition C₂S 21.65 18.61 15.66 12.69 9.75 C₄A₃ S 15    C₄AF 4.98 14.99 24.99 34.95 45.01 CŚ 4.75 Free Lime 1250° C.-30 min — — — — — (wt. %) 1250° C.-60 min — 1.85 1.14 1.38 1.20 1275° C.-30 min — 1.62 1.26 0.90 1.02 1275° C.-60 min — 0.72 0.60 0.54 0.66 1300° C.-30 min 1.50 0.30 0.24 0.30 0.30 1300° C.-60 min 0.78 — — — — 1325° C.-30 min 1.79 — — — — 1325° C.-60 min 0.60 — — — — 1350° C.-30 min 1.08 — — — —

-   -   -   -   Four compositions were formulated from industrial                 by-products (BP) as displayed in the table below.

TABLE 4 Modulus Values based on Industrial By Products. Composition number #1 #2 #3 #4 #5 Modulus LAD 0.88 0.92 0.92 0.91 0.91 Values RSA 3.30 2.32 1.39 0.85 0.54 RSF 2.38 1.44 0.71 0.45 0.32 SEC 1.20 1.53 1.57 1.63 1.71 QLP 0.10 0.10 0.10 0.10 0.10 Chemical Hydrated Lime 46.3 46.3 46.3 46.3 45.8 Formulations Bottom Ash 15.236 18.36 18.35 18.3 18.29 Red Mud 0 2.55 8.7 15 20.8 Bauxite 1 4.0 7 10 13 BF Slag Fines 24.102 17.62 10.14 3 0 Class C Fly Ash 12.7 10.52 8.87 6.77 1.5 CaF₂ 0.662 0.65 0.64 0.63 0.62 Chemical CaO 58.56 57.72 55.32 52.85 50.68 Compositions SiO₂ 19.65 17.25 14.45 11.51 8.89 Al₂O₃ 8.57 10.16 12.29 14.46 16.29 Fe₂O₃ 2.01 3.59 7.15 10.93 14.37 SO₃ 4.69 5.53 5.57 5.59 5.57 CaF₂ 0.78 0.78 0.78 0.78 0.78 Clinker C₃S 47.96 50 41.36 32.54 24.75 Composition C₂S 20.14 11.73 10.21 8.45 6.81 C₄A₃ S 14.54 15.70 15.41 14.94 14.20 C₄AF 6.11 10.91 21.77 33.25 43.73 CŚ 4.73 5.91 6.03 6.17 6.30 Free Lime 1250° C.-60 min 0.72 0.66 0.72 0.48 0.78 (wt. %)

-   -   -   -   Even though five modulus values were established,                 actually three of them have to remain constant to                 produce a clinker expecting to correspond to the                 theoretical formulations. The two other modulus values                 do not have a specific values but recommended ranges.             -   LAD=0.88; SEC=1.20; QLP=0.10; RSA>2; RSF low (close to                 0.5)             -   Others unknowns (three actually) have to be designed,                 such as the amounts of C₃S (or C₂S), C₄A₃ S, C₄AF, CŚ,                 RSF, RSA.             -   When the modulus values are selected, along with the                 theoretical clinker composition, different industrial                 by-products can be mixed to obtain the same final                 clinker composition. Endless formulations can be                 established, and the use of specific industrial                 by-products is then of great consideration depending on                 the clinker composition. This is further illustrated in                 table 5.

TABLE 5 Modulus values using additional industrial byproducts LAD 0.88 RSA 1.28 RSF 0.60 SEC 1.20 QLP 0.10 C₃S 36 C₂S 14 C₄A₃ S 15 C₄AF 24 CŚ 5 Formulations # 1 2 3 CaCO₃ 56.6 53.5 55.16 Fluorite 0 0 0.575 FGD Gypsum 6.72 0 0 Aluminum Dross 7.9 7.76 0 Pickling Sludge 1.6 1.64 0 Spurlock Bottom Ash 0 13.85 13.715 Red Mud 10.4 9.9 9.25 Bauxite 0 0 5.7 Tell City Slag 16.78 13.35 0 Coshocton Slag 0 0 5.3 Deely Class C Fly Ash 0 0 10.3 TOTAL 100 100 100

-   -   -   -   Several compositions defined by their modulus values                 were tested in order to define the optimum modulus                 values for each composition. A wide range of modulus                 values was tested, corresponding consequently to a wide                 range of A/CSA cements clinkers (high ferrite, high CSA,                 no ferrite/CSA).

    -   C. Additives and other Constituents         -   1. TIPA—triisopropanolamine         -   2. CŚ—calcium sulfate, CaSO₄         -   3. CaF₂—calcium fluoride

    -   D. “Substantially free of C₃A” means contains less than 1.0% of         tricalcium aluminate.

A hybrid cement clinker of the ferrite-alite-calcium sulfoaluminate type, exhibiting enhanced performance and environmental characteristics, includes about 20-55 weight percent C₃S, about 5-25 weight percent C₂S, about 10-20 weight percent C₄A₃ S, and about 5-50 weight percent C₄AF, about 3-7 weight percent CŚ and about 0.5 to 1.0 weight percent CaF₂. Further, the hybrid cement clinker has a LAD modulus value of between about 0.8 and about 0.96, a RSA modulus value of between about 0.3 and about 4.0, a RSF modulus value of between about 0.2 and about 4.0, a SEC modulus value of between about 0.4 and about 2.3 and a QLP modulus value of between about 0.08 and about 0.12.

In another possible embodiment the hybrid cement clinker has a LAD modulus value of between about 0.86 and about 0.94, a RSA modulus value of between about 0.5 and about 2.5, a RSF modulus value of between about 0.3 and about 1.5, a SEC modulus value of between about 1.0 and about 1.7 and a QLP modulus value of between about 0.09 and about 0.11.

In yet another possible embodiment the hybrid cement clinker comprises about 35-41 or, more particularly about 35-36, weight percent C₃S, about 10-15 or, more particularly about 14-16, weight percent C₂S, about 14-16 or, more particularly about 15, weight percent C₄A₃ S, about 20-26 or, more particularly about 24-25, weight percent C₄AF and about 4-6 or, more particularly about 5, weight percent CŚ and is fired at a temperature of about 1250-1300° C. The clinker has a LAD modulus value of between about 0.88 and about 0.92, a RSA modulus value of between about 1.0 and about 1.7, a RSF modulus value of between about 0.5 and about 0.8, a SEC modulus value of between about 1.0 and about 1.6 and a QLP modulus value of between about 0.095 and about 0.105.

In one possible embodiment of the invention the cement clinker incorporates stainless steel pickling sludge. This is a by-product of stainless steel production. In the process, the stainless steel is flooded with hydrofluoric acid (HF) which is used to clean the steel and remove contaminates like silica in the final product. The HF is neutralized with CaCO₃ which forms a CaF₂ rich sludge (P. Sludge in Table A). This material is non-hazardous but is typically not utilized and commands a disposal fee. The high content of calcium, fluoride and iron makes this material ideal for the production of the high ferrite-alite calcium sulfoaluminate cement (F/A-CSA). The CaF₂ contributes to the development of the fluorellestadite flux and the high iron to the formation of ferrite.

In another useful embodiment the cement clinker incorporates Bayer red mud. Red mud, along with brown mud, is a by-product of the Bayer process used to refine bauxite into alumina. This process uses sodium hydroxide to purify the alumina and produces an alkaline iron rich product in the form of a highly alkaline slurry. Although effort has been expended in finding uses for this material it is still considered a waste product. There are currently hundreds of millions of tons of red mud stored in facilities in North America many of which are on or near rivers and other ports. Red mud is very high in Fe₂O₃, Al₂O₃ and TiO₂ (Red Mud in Table A). Brown mud also has a high content of calcium. This material is of value for this application as it provides an important source of oxides critical to the formulation of the cement reducing the amount of bauxite in the formulation and thereby lowering clinker/cement production costs. In addition the utilization of red mud removes a long term environmental liability.

In another useful embodiment the cement clinker incorporates fluidized bed combustion spent bed material. Fluidized bed combustion (FBC) spent bed material is a by-product of the combustion of coal (CFB Ash in Table A). In this process coal is burned in the presence of limestone which reacts with the sulfur dioxide from the coal to form CaO and CaSO₄ (in the form of anhydrite). Also present are silicates from the coal ash. Although this is one of the cleanest technologies for coal combustion it has the decided disadvantage of producing up to four times more solid waste than conventional pulverized coal boilers, only a small fraction of which is utilized. This by-product is an important potential component in the formation of F/A CSA clinker, as it contributes both free lime, CaO and sulfate. The free lime contributes to the overall calcium needed in the formulation without adding carbonate, the sulfate is needed for the formation of the Klein's compound, as well as fluorellestadite.

In yet another useful embodiment, the cement clinker incorporates air cooled blast furnace slags. Much of the primary slag produced in a basic blast furnace is made cementitous and usable through rapid water quenching. This freezes the slag into a glass, which after, milling is hydraulically active and is referred to as ground granulated blast furnace slag or GGBFS. Many blast furnaces are not equipped with water quenching systems and the slags are air cooled. Air cooled slags are largely crystalline and are not, or only very weakly, hydraulically active. These materials can be used as aggregate but are more commonly disposed of.

Air cooled blast furnace slags may also be successfully used in the formulation of our F/A-CSA formulations. There inherent crystallinity did not interfere with the formation of the critical clinker compounds of the cement. These materials are plentiful and contribute CaO without CO₂ as well as reducing the cost of the materials.

In still another embodiment the cement clinker incorporates iron casting (Cupola) slags. Another category of slags that we have demonstrated to work well in the formulation of the cement clinker are cupola furnace slags from ductal and cast iron manufacturing (Iron Slag 1 and 2 in Table A). These slags are lower in iron but typically are as high in CaO and higher in Al₂O₃ content than blast furnace slags. These slags are generally produced at levels of tens of thousands of tons per year, compared to hundreds of thousands of tons for GGBFS materials. The lower quantity of production limits the capital investiture to make them hydraulic and like the air quenched blast furnace slags much of these potentially valuable materials is not utilized.

In still another possible embodiment, the cement clinker incorporates carbide lime. Carbide lime is a byproduct of acetylene manufacture. It is produced as a wet slurry and is typically dark in color due to its contamination with 1 to 2% carbon which limit its utilization to lower value applications. When dried, its chemistry (C. Lime in Table A) is very similar to that of conventional commercial hydrated lime (H. Lime in Table A). This material has been used in the formulation of F/A CSA and found to perform identically to conventional lime or limestone. It has the advantage of having very low carbonate concentration and its moisture content was found not to be a problem in formulating the clinker. Where available this is an ideal material for use in the formulation of F/A CSA. It has the advantage in increasing the flexibility of the composition of the other byproducts.

In still another possible embodiment, the cement clinker incorporates aluminum dross. Aluminum Dross is a by-product of aluminum production, and is generated at around 5 million tonnes each year. This waste material, black or white depending on the salt content, is disposed in landfill, which represents a potential environmental liability. Its high content of aluminum oxide is very advantageous as the use of this material would decrease the amount of expensive bauxite necessary for the formulation of high-iron cements, especially the calcium sulfoaluminate and ferrite clinker phases.

Of course, it should be appreciated that the cement clinker may incorporate any combination or even all of the waste materials including stainless steel pickling sludge, Bayer red mud, fluidized bed combustion spent bed material, air cooled blast furnace slags, iron casting slags, carbide lime, aluminum dross. A chemical composition of these industrial waste materials are set forth in the following Table 6.

TABLE 6 Chemical composition of industrial by products used in F/A CSA formulations CaO SiO₂ Al₂O₃ Fe₂O₃ SO₃ LOI MgO K₂O Na₂O P₂O₅ TiO₂ F Cr Sum H. Lime 65.27 1.96 1.56 0.42 0.07 29.83 2.11 0.07 0.11 0.01 0.07 — — 101.5 C. Lime 64.01 3.74 1.86 0.45 0.58 29.36 0.08 0.01 0.01 — — — — 100.1 CFB Ash 45.91 15.3 5.95 3.44 23.1 4.61 1.99 0.47 0.11 0.11 0.3 — — 101.3 Red Mud 6.96 9.41 15.33 46.5 0.44 12.81 0.45 0.18 1.59 0.74 5.7 — — 100.1 Bauxite 0.16 6.64 58.54 6.28 0.24 27.6 0.2 0.01 0.01 0.22 2.18 — — 102.1 BFSFines 38.34 37.03 10.25 1.13 0.8 0.54 10.99 0.39 0.3 0.01 0.49 — — 100.3 Iron Slag1 30.21 50.71 12.84 1.35 0.21 0 3.71 0.33 0.49 0.01 0.43 — — 100.3 Iron Slag2 36.96 46.94 8.56 1.56 0.67 0 1.47 0.38 0.06 0.02 0.36 — — 97.00 P. Sludge 51.24 3.51 0.87 15.45 7.57 0 1.11 0.02 0.24 0.04 0.15 16.1 1.5 97.7 Al Dross 0.88 4.41 64.45 2.63 0 20.02 3.85 1.20 0.67 0.07 0.23 — — 98.55 C Fly Ash 26.28 35.24 20.47 5.13 1.83 0.38 5.04 0.46 1.47 1.43 1.24 — — 99.0

Seven different formulations of cement clinker made using these waste materials with modulus values and clinker compositions as identified above are set forth in Table 7.

TABLE 7 Formulation of cement from a variety of industrial by products Formulations # 1 2 3 4 5 6 7 Modulus Values LAD 0.88 0.88 0.88 0.88 0.88 0.88 0.88 RSA 1.32 1.32 1.32 1.32 1.25 1.29 1.3 RSF 0.61 0.61 0.61 0.61 0.61 0.62 0.61 SEC 1.2 1.2 1.2 1.2 1.2 1.2 1.2 QLP 0.1 0.1 0.1 0.1 0.1 0.1 0.1 Composition of By Products Fluidized Bed Bottom Ash 13.86 13.62 0 13.39 15.35 14.2 13.9 Red Mud 9 9 9.5 8.61 11.7 9.8 9.71 Bauxite 7.6 8.5 7.6 6.3 7 0 0 Iron Slag #1 0 13.5 0 0 0 0 13.6 Iron Slag #2 12.4 0 15.4 7.68 0 12.19 0 Blastfurnace Slag 0 0 0 0 10.13 0 0 Class C Fly Ash 0 0 0 7.15 8.87 0 0 TOTAL 100 100 100 100 100 100 100 Clinker Compositions C3S 36 36 36 36 35 36 36 C2S 16 16 15 15 15 14 15 C₄A₃ S 15 15 15 15 15 15 15 C4AF 24 24 24 24 25 24 24 CŚ 5 5 5 5 5 5 5

In any of the current formulations of cement clinker, TIPA may be added to accelerate or assist the reaction of ferrite to form ettringite which helps to form a harder more stable cement paste. The hypothesis is that TIPA assists the hydration processes by reacting with the ferric iron from ferrite phase allowing an iron rich ettringite to be formed. This also prevents the formation of an iron oxide/hydroxide layer which covers the unreacted phases slowing or stopping the reaction. As a consequence, the ferrite is a fully reactive ettringite forming phase and the alite phase is also fully reactive producing C—S—H hydration products. The TIPA allows the cement paste to absorb more gypsum and then form more ettringite. The cement clinker may include between 0.05 to 1.0 weight percent of TIPA.

As should be appreciated the hybrid cement clinker may include high levels of ferrite (greater than 30% C₄AF) and lower levels of bauxite. In such a clinker, large amounts of red mud are used as a starting material. Red mud is inexpensive when compared to bauxite. Further, such a formulation employs a lower firing temperature thereby saving energy and lowering production costs. Lower CO₂ emissions are also produced as compared to ordinary portland cement. Cement clinkers rich in ferrite also require large amounts of gypsum. For example a cement clinker formulation incorporating 45% C₄AF comprises approximately 30% gypsum and 70% clinker as compared to ordinary Portland cement which typically comprises about 95% clinker and 5% gypsum. Table 8 below illustrates potential energy savings of the current cement clinker formulations.

TABLE 8 CO2-emission CO2-emission Limestone from raw from raw needed (kg/ materials (kg/ Theoretical materials (kg/ t clinker) - t clinker) - amount of t cement) - Compared Compared gypsum needed Compared to OPC to OPC (kg/t cement) to OPC #1-BP 675-43.8% 466-11.7% 6 438-16.6% #2-BP 687-42.8% 441-16.5% 13 384-26.9% #3-BP 700-41.7% 417-21.0% 20 334-36.5% #4-BP 713-40.6% 396-25.0% 27 289-45.0% #5-BP 725-39.6% 379-28.2% 33 262-50.1% OPC 1200 528 5 525 OPC values above taken from Gartner patent for comparison with our compositons

In one particularly useful embodiment the cement clinker formulation is substantially free of C₃A. The lack of C₃A (along with low free lime) indicates that the proper firing regime, i.e. time and temperature, has been achieved. High free lime (i.e. greater than 1%) indicates that the clinker is not fully reacted and high C₃A indicates that the clinker has been “over-fired” and the Klein's compound has begun to decompose. In the cement itself if unregulated (i.e. under-sulfated), C₃A can induce flash set during hydration and result in cracking. In another particularly useful embodiment the cement clinker includes between 675-725 kg of limestone per ton of clinker.

The cement clinker and a cement incorporating a cement clinker may be made in accordance with the following general method. Typically the cement includes between about 65 and about 95 weight percent clinker and between about 5 and about 35 weight percent gypsum. In one useful embodiment the cement includes between about 78 and about 82 weight percent clinker and between about 18 and about 22 weight percent gypsum.

Step 1: Many byproducts are already fine in nature for those that are not they must be ground finely to reach a small particle size, this may vary but finer is better, with sizes as small as ˜15 um desirable.

Step 2: Mix all the raw materials until the materials are intimately associated.

Step 3: Fire the mixture in a rotary kiln pellets following the correct firing regime for each composition:

-   -   Room Temperature up to 800° C. for 30 minutes, followed by up to         1250/1275/1300° C. for 60 minutes.

Step 4: Quench the pellets formed in air.

Step 5: Grind the pellets to a particle size close to 15 μm.

Step 6: Grind the clinker with the appropriate amount of gypsum to optimize the clinker properties, which depends on the clinker composition and the theoretical amount of gypsum required to completely hydrate C₄A₃ S and C₄AF clinker phases.

This process is identical for any kind of raw materials used.

The following examples are provided to further illustrate the novel cement clinker but it is not to be considered as limited thereto.

Example 1

This example illustrates the feasibility to produce a clinker comprising 36% C₃S, 14% C₂S, 15% C₄A₃Ś, 24% C₄AF and 5% CŚ, with modulus values of 0.88 for LAD, 1.28 for RSA, 0.60 for RSF, 1.20 for SEC and 0.10 for QLP from exclusively industrial by-products. Using the procedures describe above limestone, FGD gypsum, aluminum dross, pickling sludge, red mud, and an iron slag in the proportions in Table 9 are blended together and fired in a rotary kiln to form a clinker.

TABLE 9 Other examples of industrial byproduct usage. Raw Materials Clinker Phases Moduli CaCO₃ 56.6 C₃S 36 LAD 0.88 FGD Gypsum 6.72 C₂S 14 RSA 1.28 Aluminum Dross 7.9 C₄A₃Ś 15 RSF 0.60 Pickling Sludge 1.6 C₄AF 24 SEC 1.20 Red Mud 10.4 CŚ 5 QLP 0.10 Iron Slag #1 16.78

Example 2

This example describes the fabrication of a similar clinker to example 1, using the procedures described above. Limestone, fluidized bed bottom ash, bauxite, fluorite, red mud, iron slag #2, and class C fly ash in the proportions described in Table 10 are mixed and fired in a rotary kiln to form a clinker.

TABLE 10 Other examples of industrial byproduct usage. Raw Materials Clinker Phases Moduli CaCO₃ 55.16 C₃S 36 LAD 0.88 Fluidized Bed Bottom Ash 13.715 C₂S 14 RSA 1.28 Bauxite 5.7 C₄A₃Ś 15 RSF 0.60 Fluorite 0.575 C₄AF 24 SEC 1.20 Red Mud 9.25 CŚ 5 QLP 0.10 Iron Slag #2 5.3 Class C Fly Ash 10.3

Example 3

This example describes the fabrication of a similar clinker to examples 1 and 2, with different by-products as raw materials. Using the procedures described above carbide lime, FGD Gypsum, aluminum dross, pickling sludge, red mud, blastfurnace slag, and Class C fly ash in the proportions of Table 11 are fired in a rotary kiln to form a clinker.

TABLE 11 Other examples of industrial byproduct usage. Raw Materials Clinker Phases Moduli Ca(OH)₂ 49.4 C₃S 36 LAD 0.88 FGD Gypsum 7.0 C₂S 14 RSA 1.28 Aluminum Dross 5.3 C₄A₃Ś 15 RSF 0.60 Pickling Sludge 1.8 C₄AF 24 SEC 1.20 Red Mud 10.6 CŚ 5 QLP 0.10 Blastfurnace slag 11.0 Class C fly ash 14.9

Example 4

This example describes the fabrication of a high iron—high ferrite containing clinker. Using the procedures described above carbide lime, FGD Gypsum, aluminum dross, pickling sludge, red mud, and Class C fly ash in the proportions indicated in Table 12 are mixed and fired in a rotary kiln to form a clinker.

TABLE 12 Other examples of industrial byproduct usage. Raw Materials Clinker Phases Moduli Ca(OH)₂ 47.26 C₃S 22 LAD 0.90 FGD Gypsum 10.0 C₂S 7 RSA 0.49 Aluminum Dross 13.5 C₄A₃Ś 19 RSF 0.50 Pickling Sludge 1.74 C₄AF 39 SEC 1.55 Red Mud 19 CŚ 6 QLP 0.10 Class C fly ash 8.5

Example 5

This example describes the fabrication of a clinker high in alite. Using the procedures described above carbide lime, FGD Gypsum, pickling sludge, red mud, and Class C fly ash, in the proportions of Table 13, are mixed and fired in a rotary kiln to form a clinker.

TABLE 13 Other examples of industrial byproduct usage. Raw Materials Clinker Phases Moduli Ca(OH)₂ 52.95 C₃S 50 LAD 0.95 FGD Gypsum 8.5 C₂S 7 RSA 1.94 Class C fly ash 31.75 C₄A₃Ś 13 RSF 0.77 Pickling Sludge 1.8 C₄AF 17 SEC 1.98 Red Mud 5 CŚ 7 QLP 0.10

Example 6

This example illustrates the influence of the firing regime, more specifically the firing temperature and dwell time, on the free lime content of the formulations of Table 3, which contain different contents of ferrite. Less than 1% free lime is considered to be indicative of proper clinker formation, The “+” sign alongside the free lime content in Table 14 indicates the tricalcium aluminate (from XRD analyzes) is clearly present in the sample. A high firing temperature leads to the formation of tricalcium aluminate, which indicates that the C₄A₃Ś phase is decomposing. It is illustrated that high iron and ferrite content contribute to the decrease in kiln temperature needed for clinker formation.

TABLE 14 Free lime as a function of firing regime. Firing regime #1 #2 #3 #4 #5 1250° C.-60 min — 1.85 1.14 1.38 1.20 1275° C.-30 min — 1.62 1.26 0.90 1.02 1275° C.-60 min — 0.72 0.60 0.54 0.66 1300° C.-30 min 1.50 0.30 (+) 0.24 (+) 0.30 (+) 0.30 (+) 1300° C.-60 min 0.78 — — — — 1325° C.-30 min 1.79 — — — — 1325° C.-60 min 0.60 — — — — 1350° C.-60 min 1.08 (+) — — — —

The foregoing has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the embodiments to the precise form disclosed. Obvious modifications and variations are possible in light of the above teachings. All such modifications and variations are within the scope of the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled. 

1. A hybrid cement clinker, comprising: about 20-55 weight percent C₃S; about 5-25 weight percent C₂S; about 10-20 weight percent C₄A₃ S; about 5-50 weight percent C₄AF; about 3-7 weight percent CŚ; and about 0.5-1.0 weight percent CaF₂; wherein said clinker has a lime adequate degree (LAD) modulus value of between about 0.8 and 0.96, a ratio of silicates and aluminates (RSA) modulus value of between about 0.3 and 4.0, a ratio of sulfoaluminates and ferroaluminates (RSF) modulus value of between about 0.2 and 4.0, a sulfur excessive coefficient (SEC) modulus value of between about 0.4 and 2.3 and a quantity of liquid phase (QLP) modulus value of between about 0.08 and 0.12.
 2. The cement clinker of claim 1 wherein said clinker has a lime adequate degree (LAD) modulus value of between 0.86 and 0.94, a ratio of silicates and aluminates (RSA) modulus value of between 0.5 and 2.5, a ratio of sulfoaluminates and ferroaluminates (RSF) modulus value of between 0.3 and 1.5, a sulfur excessive coefficient (SEC) modulus value of between 1.0 and 1.7 and a quantity of liquid phase (QLP) modulus value of between 0.09 and 0.11.
 3. The cement clinker of claim 1 incorporating stainless steel pickling sludge.
 4. The cement clinker of claim 1 incorporating Bayer red mud.
 5. The cement clinker of claim 1 incorporating fluidized bed combustion spent bed material.
 6. The cement clinker of claim 1 incorporating air cooler blast furnace slag.
 7. The cement clinker of claim 1 incorporating iron casting slag.
 8. The cement clinker of claim 1 incorporating carbide lime.
 9. The cement clinker of claim 1 incorporating aluminum dross.
 10. The cement clinker of claim 1, further including between 0.2 and 1.0 weight percent of TIPA.
 11. The cement clinker of claim 1, wherein said clinker is substantially free of C₃A.
 12. The cement clinker of claim 1, further including between 675-725 kg of limestone per ton of clinker.
 13. The cement clinker of claim 1, further including between 0.05 and 1.0 weight percent of TIPA and between 0.7 and 0.85 weight percent of CaF₂.
 14. A cement made from said clinker of claim
 1. 15. The cement of claim 14 including between about 65 and about 95 weight percent clinker and between about 5 and about 35 weight percent gypsum.
 16. A cement made from said clinker of claim
 2. 17. The cement of claim 16 including between about 65 and about 95 weight percent clinker and between about 5 and about 35 weight percent gypsum
 18. A cement clinker, comprising: about 35-41 weight percent C₃S; about 10-15 weight percent C₂S; about 14-16 weight percent C₄A₃ S; about 20-26 weight percent C₄AF; about 4-6 weight percent CŚ; and about 0.7-0.85 weight percent CaF₂; fired at a temperature of about 1250-1300° C.
 19. The clinker of claim 18 having a lime adequate degree (LAD) modulus value of between 0.88 and 0.92, a ratio of silicates and aluminates (RSA) modulus value of between 1.0 and 1.7, a ratio of sulfoaluminates and ferroaluminates (RSF) modulus value of between 0.5 and 0.8, a sulfur excessive coefficient (SEC) modulus value of between 1.0 and 1.6 and a quantity of liquid phase (QLP) modulus value of between 0.095 and 0.105. 